Skip to main content

A Guide to the Flu Vaccine Cold Chain: Storage & Transport

Life Sciences

closeup of flu vaccine vials with syringe

As the seasons change and the temperature drops, preparations for the flu season begin. When immunization efforts start, the flu vaccine is shipped with cold chain safeguards from the moment it leaves.

The flu vaccine's journey once it leaves its manufacturer is designed to maintain the temperatures that keep the vaccine safe and effective. This critical part of the immunization process involves the use of refrigeration technology and specialized temperature monitors to ensure temperature conditions remain consistent from manufacture to the moment of injection.

To better understand how the flu vaccine cold chain works, let’s review the processes, regulations, and best practices that help to ensure the vaccine reaches patients safely.

An Overview of the Flu Vaccine Cold Chain

The flu vaccine cold chain is a temperature-controlled supply chain that ensures the safe storage and transportation of flu vaccines from the point they leave the manufacturer to their arrival at their administration site. It involves continually trying to maintain the temperature conditions that preserve the vaccine's potency and effectiveness.

As the upcoming flu season approaches, understanding and adhering to the flu vaccine cold chain process is essential for pharmaceutical companies and healthcare providers.

The Ideal Temperature of the Flu Vaccine During Storage & Transport

The flu vaccine must be kept at a temperature between 2°C and 8°C (35°F and 46°F) during both storage and transport. Deviations from this range, such as freezing temperatures, can compromise the vaccine's integrity and render it ineffective.

Best Practices for Flu Vaccine Transport

When transporting flu vaccines, several best practices can help maintain the cold chain and ensure vaccine efficacy:

Load Product at the Correct Temperature

The vehicle and insulated containers used to transport the vaccine should be pre-conditioned to the correct temperature before packaging and loading, so that the flu vaccine is not exposed to temperatures outside of its recommended range. This initial step prevents temperatures from moving above the product’s limits at the start of its journey.

Do Not Place Product Close to Walls of the Truck

The walls of the truck are more subject to temperature fluctuations from ambient conditions outside of the truck, so placing vaccine products close to the walls should be avoided. Leaving the walls clear also improves airflow, ensuring a more consistent temperature during shipping.

Consider the Truck Route

External weather conditions can affect internal temperatures, but they can be mitigated with good planning. One example is a shipment moving from north to south in the northern hemisphere, which will result in the back of the truck facing the sun during transit. Care should be taken when loading the truck and setting up its temperature monitoring to mitigate the effects of potential temperature fluctuations.

For longer cross-country trips, drivers may reach the limit of their driving time (often ten hours) before the delivery is completed. Plans should be made to either relay drivers or build in contingencies to maintain temperatures during any driver downtime.

Ensure that the Flu Vaccine Stays in the Right Temperature Range

It is critical to ensure that the flu vaccine stays in the proper refrigerated temperature range, which is usually 2°C to 8°C (35°F to 46°F). Exposure to temperatures outside this range can affect the vaccine’s stability, rendering it ineffective or even unsafe to administer. Many vaccines, including the flu vaccine, become unusable when exposed to freezing temperatures and must be discarded. This is a common problem causing vaccine wastage: a recent study found 16.7% of vaccines are accidentally frozen during transport.

To maintain the correct temperature range, qualified refrigeration equipment must be used, and validated and accurate temperature monitors must check and record temperature for assurance that the cold chain was maintained during all transportation and storage between manufacturer and administration. All refrigeration equipment should be set to a temperature of 5°C, the middle of the acceptable range.

Ensure Vaccine is Not in Direct Contact with Ice

The flu vaccine, like many other refrigerated vaccines, is susceptible to degradation when exposed to freezing temperatures. Storing or transporting the flu vaccine in direct contact with ice or frozen gel packs substantially increases the risk of the vaccine freezing and must be avoided. Ensure proper insulation and separation to prevent any direct contact between the vaccine and ice.

Invest in Real-Time Monitoring and Prevent Supply Chain Disruptions

Although vaccines are often transported with simple electronic indicators that provide a yes/no answer to whether temperature conditions were maintained during transportation, real-time monitoring solutions like the TempTale® GEO Ultra can alert logistics and pharmaceutical companies to temperature issues the moment they occur, providing the opportunity to intervene and prevent a shipment from being wasted. Similarly, digital solutions that help to predict supply chain disruptions like Lynx Logix™ and a real-time stationary monitoring solution like ColdStream® Site can monitor temperatures continually during storage, providing actionable alerts and insights.

Additional benefits of these solutions utilize the detailed data they provide to optimize a shipping lane or storage area, helping to prevent future temperature issues.

Best Practices for Flu Vaccine Storage

Proper storage is crucial for maintaining the flu vaccine's efficacy. Here are some best practices for flu vaccine storage:

Have a Refrigerator Specific for the Flu Vaccine

The U.S. Centers for Disease Control and Prevention (CDC) recommends having a dedicated refrigerator used only for storing vaccines. This must be a stand-alone unit, which provide more consistent temperature control and also reduce the risk of freezing temperatures reaching the flu vaccine.

Although household-grade refrigerators may be used where necessary, purpose-built refrigeration units that are designed for biologics will provide better air circulation for uniform temperature, and can recover correct temperatures more quickly. Temperatures must be monitored within all flu vaccine storage units.

Identify Areas Susceptible to Fluctuations in Temperature

A thermal mapping study, sometimes called a temperature mapping study, places temperature monitoring sensors throughout a storage area to identify temperature fluctuations. This process helps identify areas prone to temperature variations, which enables better temperature control. Thermal mapping is a regulatory requirement for vaccine storage in many parts of the world.

Have a Plan if Vaccine Temperature Falls out of Range

It is important to have a plan for if vaccine temperature falls out of range. This can prevent wastage or the administration of ineffective vaccines.

To handle flu vaccine temperature excursions effectively, an action plan should include the following steps:

Step Action
Notify Immediately report issues and label exposed vaccines as “do not use.”
Document Document all details of the excursion, including date, time, and temperature.
Contact Contact manufacturers or immunization program for guidance.
Correct Address the issue, fixing faulty refrigeration equipment.

Avoid Light

Light incursion can affect the stability of vaccines. For this reason, the best practice is to avoid light when storing or transporting the flu vaccine.

Both the CDC and the UK National Health Service (NHS) recommend storing vaccines in their packaging, which protects from light while also making inventory management easier and ensuring the manufacturer’s label-stated temperature ranges are visible.

Control Inventory

Limiting inventory is best practice for all vaccines to reduce wastage. The Rhode Island Department of Health Vaccine Handling and Storage Guide recommends maintaining a two-to-four-week stock of flu vaccine doses to prevent vaccine expiration. Note that this is a shorter time period than for other vaccines, so existing processes may need to be updated.

Regulations in the Flu Vaccine Cold Chain

The flu vaccine is subject to regulations that provide overarching principles for the proper storage and handling of vaccines, such as temperature control, inventory management, storage equipment requirements, and documentation procedures.

The specific regulations that apply vary based on the region in which the flu vaccine is being transported or stored. However, it is important to be familiar with EU GDP guidelines, USP <1079>, USP <659>, the CDC’s Vaccine Storage and Handling Pink Book, and the WHO’s Guidelines on the International Packaging and Shipping of Vaccines. All detail the regulatory requirements and best practice guidelines for transporting and storing vaccines.

Common components of each document are:

  • Utilizing appropriate equipment to always maintain the flu vaccine at its required temperature
  • Monitoring the temperature of the flu vaccine using a highly accurate temperature monitor with certificate of calibration
  • Appropriately documenting any excursions or temperature issues
  • Using qualified insulated packaging for shipping
  • Storing the flu vaccine in a stand-alone refrigerator, with accurate temperature monitoring
  • Qualification of shipping lanes and thermal mapping of storage environments

Sensitech’s experts can provide more thorough guidance to help advise whether your vaccine storage program is regulatory compliant.

Final Thoughts

It is essential to maintain the integrity of the flu vaccine cold chain through proper storage and transport practices. Following recommended guidelines, investing in temperature monitoring systems, and staying informed about regulations will contribute to a successful flu vaccination campaign.

Sensitech provides a range of vaccine temperature monitoring solutions, from WHO approved electronic indicators to real-time visibility and facility monitoring.

To learn more about how our monitoring solutions and expertise can support your pharmaceutical cold chain operations, sign up for our Newsletter.

Newsletter signup graphic

Frequently Asked Questions about Storage and Transport of Flu Vaccines

The cold chain system for vaccines refers to the process of continually maintaining specific temperature conditions during the storage and transportation of vaccines to ensure they remain effective when they arrive at their administration site. Maintaining this temperature range requires the use of specialized equipment, such as refrigerated trucks, pharmaceutical grade refrigerators, and highly accurate temperature monitoring devices.

Exposure to any temperatures outside of the vaccine’s stated temperature range is considered a breach of the cold chain. However, a single instance of temperature rising above +8°C does not require further action provided it lasted less than 20 minutes. Some vaccine manufacturers provide additional information on stability at unrefrigerated temperatures, which can be used to determine whether an excursion has affected vaccine quality.

The shelf life of a flu vaccine vial varies depending on the manufacturer and formulation. Always check the vaccine's packaging for expiration dates and storage recommendations.

Transporting refrigerated vaccines requires adherence to strict temperature controls and best practices. Vaccines should be loaded at the correct temperature, placed in insulated containers, kept away from truck walls, monitored with validated temperature monitoring systems, and protected from freezing temperatures and light exposure.